On 2016/06/03 at 10:06, Dave Young wrote:
Hi, Xunlei
On 05/26/16 at 09:08pm, Xunlei Pang wrote:
There are some complaints about nfs kdump that users must mount nfs beforehand, which may cause some overhead to nfs server. For example, there're thounsands of diskless clients deployed with nfs dumping, each time the client is boot up, it will trigger kdump rebuilding so will mount nfs, thus resulting in thousands of nfs request concurrently imposed on the same nfs server.
We introduce a new way of specifying mount information via the already-existent "dracut_args" directive(so avoid adding extra directives in /etc/kdump.conf), we will skip all the filesystem mounting and checking stuff for it. So it can be used in the above-mentioned nfs scenario to avoid severe nfs server overhead.
Specifically, if there is any "--mount" information specified via "dracut_args" in /etc/kdump.conf, always use it as the final mount without any validation(mounting or checking like mount options, fs size, etc), so users are expected to ensure its correctness.
When doing nfs mount via "dracut_args", because nfs needn't to be mounted beforehand, some nfs-related ko modules must be explicitly specified as needed together in the "dracut_args"(or via directive "extra_modules" in /etc/kdump.conf). As an nfs example: dracut_args --mount "192.168.1.1:/test /test nfs defaults" --add-driver "nfs nfsv4"
NOTE: -Only one mount target is allowed using "dracut_args" globally. -Dracut will create <mountpoint> if it doesn't exist in kdump kernel, <mountpoint> must be specified in an absolute path. -There must be double quotation marks behind "--mount", i.e. --mount "<mount info>". -Users should do a test first and ensure it works because kdump does not prepare the mount and check all the validity.
Suggested-by: Dave Young dyoung@redhat.com Signed-off-by: Xunlei Pang xlpang@redhat.com
dracut-kdump.sh | 6 +++++- dracut-module-setup.sh | 5 +++++ kdump-lib.sh | 41 ++++++++++++++++++++++++++++++++++++++++- kdumpctl | 13 ++++++++++++- mkdumprd | 3 +++ 5 files changed, 65 insertions(+), 3 deletions(-)
diff --git a/dracut-kdump.sh b/dracut-kdump.sh index 4aab205..8747dba 100755 --- a/dracut-kdump.sh +++ b/dracut-kdump.sh @@ -117,7 +117,7 @@ save_vmcore_dmesg_ssh() { get_host_ip() { local _host
- if is_nfs_dump_target || is_ssh_dump_target
- if is_nfs_dump_target || is_ssh_dump_target || does_dracut_args_contain_nfsmount
I may miss previous discussion, but "does_dracut_args_contain_nfsmount" looks too long and does+contains uses 12 characters. How about drop it and move the logic to is_nfs_dump_target()
BTW, what is the difference between is_nfs_in_dracut_args and does_dracut_args_contain_nfsmount Can it be like below?
The difference is is_nfs_in_dracut_args has an argument, while the other doesn't have.
get_dracut_args() { echo dracut_args config value in kdump.conf if have any }
We still need to identify the proper dracut_args, as there might be multiple dracut_args (though only one of them is allowed to be with a target specified).
is_nfs_dump_targte() { ...
dargs=get_dracut_args() return is_nfs_in_dracut_args $dargs... }
then kdumpnic=$(getarg kdumpnic=) [ -z "$kdumpnic" ] && echo "kdump: failed to get kdumpnic!" && return 1@@ -146,6 +146,10 @@ read_kdump_conf() # remove inline comments after the end of a directive. config_val=$(strip_comments $config_val) case "$config_opt" in
dracut_args)config_val=$(get_dracut_args_target "$config_val")[[ -n "$config_val" ]] && add_dump_code "dump_fs $config_val";; ext[234]|xfs|btrfs|minix|nfs) add_dump_code "dump_fs $config_val" ;;diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh index 4cd7107..5f03558 100755 --- a/dracut-module-setup.sh +++ b/dracut-module-setup.sh @@ -433,6 +433,11 @@ kdump_install_conf() { ssh|nfs) kdump_install_net "$config_val" ;;
dracut_args)if is_nfs_in_dracut_args "$config_val"; thenkdump_install_net "$(get_dracut_args_target "$config_val")"fi;; kdump_pre|kdump_post|extra_bins) dracut_install $config_val ;;diff --git a/kdump-lib.sh b/kdump-lib.sh index fc2c036..a486db6 100755 --- a/kdump-lib.sh +++ b/kdump-lib.sh @@ -45,7 +45,8 @@ is_fs_dump_target()
is_user_configured_dump_target() {
- return $(is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target || is_fs_dump_target)
- return $(does_dracut_args_contain_mount || is_ssh_dump_target || is_nfs_dump_target || \
is_raw_dump_target || is_fs_dump_target)}
strip_comments() @@ -279,3 +280,41 @@ is_hostname() fi echo $1 | grep -q "[a-zA-Z]" }
+# If "dracut_args" contains "--mount" information, use it +# directly without any check(users are expected to ensure +# its correctness). +does_dracut_args_contain_mount()
How about using a simpler name is_dracut_args_target? is_darcut_args_target() { local ... dargs=get_dracut_args() target=get_dracut_args_target $dargs if [ -n $target ] then return true else return false }
I'm fine with the naming of "is_dracut_args_target", but for the approach, we still need the logic to be implemented in get_dracut_args() as I explained above.
Regards, Xunlei
+{
- return $(grep ^dracut_args /etc/kdump.conf | grep -q "--mount")
+}
+does_dracut_args_contain_nfsmount() +{
- local fstype
- fstype=$(grep "^dracut_args .*--mount" /etc/kdump.conf | sed "s/.*--mount "(.*)/\1/" | cut -d' ' -f3)
- [[ $fstype = nfs* ]] && return 0
- return 1
+}
+# $1: configuration value of "dracut_args". +is_nfs_in_dracut_args() +{
- [[ $(get_dracut_args_fstype "$1") = nfs* ]] && return 0
- return 1
+}
+# $1: configuration value of "dracut_args". +get_dracut_args_fstype() +{
- echo $1 | grep "--mount" | sed "s/.*--mount "(.*)/\1/" | cut -d' ' -f3
+}
+# $1: configuration value of "dracut_args". +get_dracut_args_target() +{
- echo $1 | grep "--mount" | sed "s/.*--mount "(.*)/\1/" | cut -d' ' -f1
+} diff --git a/kdumpctl b/kdumpctl index fcc9ad0..fbed66d 100755 --- a/kdumpctl +++ b/kdumpctl @@ -236,12 +236,18 @@ check_config() { local nr
- nr=$(awk 'BEGIN{cnt=0} /^raw|^ssh[[:blank:]]|^nfs|^ext[234]|^xfs|^btrfs|^minix/{cnt++} END{print cnt}' $KDUMP_CONFIG_FILE)
nr=$(awk 'BEGIN{cnt=0} /^raw|^ssh[[:blank:]]|^nfs|^ext[234]|^xfs|^btrfs|^minix|^dracut_args .*--mount/{cnt++} END{print cnt}' $KDUMP_CONFIG_FILE) [ $nr -gt 1 ] && { echo "More than one dump targets specified." return 1 }
nr=$(grep "^dracut_args .*--mount" $KDUMP_CONFIG_FILE | grep -o "--mount" | wc -l)
[ $nr -gt 1 ] && {
echo "More than one mount targets specified in \"dracut_args\"."return 1}
while read config_opt config_val; do # remove inline comments after the end of a directive. config_val=$(strip_comments $config_val)
@@ -365,6 +371,11 @@ check_dump_fs_modified() local _new_dev _new_mntpoint _new_fstype local _target _path _dracut_args
- # No need to check in case of mount target specified via "dracut_args".
- if does_dracut_args_contain_mount; then
return 0- fi
- # No need to check in case of raw target. # Currently we do not check also if ssh/nfs target is specified if is_ssh_dump_target || is_nfs_dump_target || is_raw_dump_target; then
diff --git a/mkdumprd b/mkdumprd index 78afb1a..7a0e733 100644 --- a/mkdumprd +++ b/mkdumprd @@ -544,6 +544,9 @@ do verify_core_collector "$config_val" ;; dracut_args)
if is_nfs_in_dracut_args "$config_val"; thenadd_dracut_module "nfs"fi add_dracut_arg $config_val ;;-- 1.8.3.1 _______________________________________________ kexec mailing list kexec@lists.fedoraproject.org https://lists.fedoraproject.org/admin/lists/kexec@lists.fedoraproject.org